package com.lagou.rpc.provider.handler;

import com.alibaba.fastjson.JSON;
import com.lagou.rpc.common.RpcRequest;
import com.lagou.rpc.common.RpcResponse;
import com.lagou.rpc.provider.anno.RpcService;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import org.springframework.beans.BeansException;
import org.springframework.cglib.reflect.FastClass;
import org.springframework.cglib.reflect.FastMethod;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 服务端业务启动类
 *   1.将标有@RpcService注解的bean缓存
 * * 2.接收客户端请求
 * * 3.根据传递过来的beanName从缓存中查找到对应的bean
 * * 4.解析请求中的方法名称. 参数类型 参数信息
 * * 5.反射调用bean的方法
 * * 6.给客户端进行响应
 */
@Component
@ChannelHandler.Sharable
public class RpcServerHandler extends SimpleChannelInboundHandler<String>  implements ApplicationContextAware {

    //定义一个bean缓存对象
    private static final Map SERVICE_INSTANCE_MAP = new ConcurrentHashMap();

    /**
     * 1.将标有@RpcService注解的bean缓存
     * @param applicationContext
     * @throws BeansException
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        Map<String, Object> serviceMap = applicationContext.getBeansWithAnnotation(RpcService.class);
        if(serviceMap!=null&&serviceMap.size()>0){
            Set<Map.Entry<String, Object>> entries = serviceMap.entrySet();
            for (Map.Entry<String, Object> item : entries) {
                Object serviceBean = item.getValue();
                if (serviceBean.getClass().getInterfaces().length==0){
                    throw new RuntimeException("服务必须实现接口");
                }
                //默认取第一个实现接口为bean存放缓存的名称
                String name = serviceBean.getClass().getInterfaces()[0].getName();
                SERVICE_INSTANCE_MAP.put(name,serviceBean);
            }
        }
    }

/*
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("=============客户端："+ctx.channel().remoteAddress().toString().substring(1)+"连接成功==========================");

    }
*/

    /**
     * 通道读取就绪事件
     * @param ctx
     * @param msg
     * @throws Exception
     */
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        //2.接收客户端请求----将msg转化成RpcRequest对象
        RpcRequest rpcRequest = JSON.parseObject(msg, RpcRequest.class);
        //new一个响应对象
        RpcResponse rpcResponse = new RpcResponse();
        rpcResponse.setRequestId(rpcRequest.getRequestId());
        try {
            rpcResponse.setResult(handler(rpcRequest));
        }catch (Exception e){
            e.printStackTrace();
            rpcResponse.setError(e.getMessage());
        }
        //6.给客户端进行响应
        ctx.writeAndFlush(JSON.toJSONString(rpcResponse));
    }

    private Object handler(RpcRequest rpcRequest) throws InvocationTargetException {
        //3.根据传递过来的beanName从缓存中查找到对应的bean
        Object serviceBean = SERVICE_INSTANCE_MAP.get(rpcRequest.getClassName());
        if (serviceBean==null){
            throw new RuntimeException("根据传递过来的beanName找不到服务，beanName:"+rpcRequest.getClassName());
        }
        //4.解析请求中的方法名称. 参数类型 参数信息
        Class<?> serviceBeanClass = serviceBean.getClass();
        String methodName = rpcRequest.getMethodName();
        Class<?>[] parameterTypes = rpcRequest.getParameterTypes();
        Object[] parameters = rpcRequest.getParameters();
        //5.反射调用bean的方法  使用CBLIB反射Method.invoke()
        FastClass fastClass = FastClass.create(serviceBeanClass);
        FastMethod method = fastClass.getMethod(methodName, parameterTypes);
        return method.invoke(serviceBean,parameters);
    }

}
